Code Biases in Multi-GNSS Point Positioning

Abstract

Pseudorange measurements collected with Global Navigation Satellite System (GNSS) receivers are known to exhibit systematic offsets related to delays in the analogue or digital part of the overall signal generation, transmis-sion and processing chain. In a multi-GNSS context, measurements obtained from different signals, frequencies and constellations need to be processed along with each other and a proper consideration of biases becomes mandatory for a consistent modeling of all observations. The present report discusses code biases in multi-GNSS measurements from first principles and presents a consistent framework for their consideration in multi-GNSS data analysis. Other than with legacy GPS signals, the wide range of GNSS signals today results in an inflation-ary number of differential code biases (DCBs) that may need to be considered in practical multi-GNSS work. An efficient algorithm is proposed to obtain DCBs for arbitrary signal pairs from a self-consistent, minimal set of reference DCBs. Even though no standard set of DCBs for multi-GNSS work has yet emerged, the proposed algorithm can be used as a basis for future DCB products prepared by and for the geodetic community.